As is known, a substrate (sometimes also referred to in the art as an interposer) is a device that provides a fan-out between I/O (i.e., electrical inputs and outs) of a circuit, for example and without limitation, an integrated circuit (“IC”) and a Probe Card to enable testing of the IC, for example, at a wafer level. Such a substrate may be a rigid substrate, a semi-flex substrate, a flex substrate, and so forth, and such substrates often have a relatively low cost when compared to that of the Probe Card.
As IC geometries have decreased in size dramatically since such devices were first introduced several decades ago, so too have geometries associated with wiring connections to their I/O. For example, present designs include the use of bumped wafer pad pitches of 200 μm or less. In order to test such ICs, one is required to utilize high density interconnect (“HDI”) substrates having matching fine connector pitches.
Substrates available today, and the manner in which they are used, are problematic for two basic reasons. First, manufacturing techniques used to fabricate such substrates and to connect them to Probe Cards typically require multiple expensive steps. Second, if one of the connectors on the substrate gets damaged, it cannot be replaced, for the most part, or is difficult or expensive to rework. In addition, whenever the substrate wears out, or gets damaged, one typically has to throw away the Probe Card together with the substrate. In particular, this is because, due to manufacturing techniques used to fabricate such substrates and to connect them to Probe Cards, it is a prohibitively lengthy and costly process to separate the substrate from the Probe Card.
In light of the above, there is a need in the art for: (a) one or more structures useful, for example and without limitation, for testing circuits, for example and without limitation, ICs at a wafer level that solve one or more of the above-identified problems; and (b) one or more methods for fabricating such structures.